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Modern capacitor values
12/3/2006 8:51:49 PMMartin M.
When replacing caps in a radio is it ok to vary values from the originals. ie originals are .04 and .05, should I use .047(common value) for both or are there cases where I need to keep things exact. I know in transocianics you have to keep the filament resistors exactly at 970ohms so you have to use parallel resistance to math them up.
12/3/2006 9:40:50 PMNorm Leal
Hi Martin

Yes it's ok to use a modern value that's close to the original cap. All caps have tolerance anyway.

Resistors are the same way. Plus or minus 10% or more doesn't make a difference in radio operation.

Keeping the same value filament dropping resistor is a good idea. This controls voltage to each tube filament. Even these resistors have a tolerance. With higher line voltage you may want to increase a 970 ohm wire wound to 1000 ohms or more. Adjust until filament is around 1.4 volts.

Norm


:When replacing caps in a radio is it ok to vary values from the originals. ie originals are .04 and .05, should I use .047(common value) for both or are there cases where I need to keep things exact. I know in transocianics you have to keep the filament resistors exactly at 970ohms so you have to use parallel resistance to math them up.



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